163 Questions
Which cell structure is unique to plant cells and not present in animal cells?
Cell wall
What is the primary function of chloroplasts in plant cells?
Use light to create food (glucose)
Which process is common to both prokaryotic and eukaryotic cells?
Transcription of DNA into RNA
What is a key characteristic that distinguishes prokaryotic cells from eukaryotic cells?
Presence of a membrane-bound nucleus
Why is cellular diversity important in building complex organisms like the human body?
To allow for better adaptation of cells
Which organelle is exclusive to eukaryotic cells and plays a crucial role in generating energy?
Mitochondria
What is the function of pili and flagella structures in prokaryotic cells?
Allow for movement
What is a key characteristic of microtubules in the cytoskeleton?
They consist of dimers of α- and γ-Tubulin
What role do Microtubule Organizing Centres (MTOCs) play in cells?
Replicate to form two distinct MTOCs before cell division starts
How do the proteins forming the cytoskeleton resemble LEGO pieces?
They assemble into a wide range of structures by fitting together
Why is the dynamic nature of the cytoskeleton essential for its functions?
For polymers and regulatory proteins to be constantly in flux
Which type of microtubules is primarily involved in connecting sister chromatids to the spindle apparatus during cell division?
Kinetochore Microtubules
In what aspect are microfilaments different from microtubules?
Microfilaments are made of actin subunits while microtubules are made of tubulin subunits.
What role do intermediate filaments play in the cell's response to mechanical stresses?
They cross-link with other cytoskeletal elements like microtubules and microfilaments.
What is the primary function of actin filaments in endocytosis?
Creating a contractile ring around the cell's 'waist'
How do pathogens manipulate the host cytoskeleton?
Through interactions with extracellular receptors and intracellular signaling pathways
What distinguishes intermediate filaments from microtubules and microfilaments?
Intermediate filaments are highly divergent in sequence and molecular weight.
How does ATP provide energy in cellular reactions?
By transferring a phosphate group to another molecule in phosphorylation
What is the primary role of mitochondria in the cell?
To generate ATP through cellular processes
In cellular respiration, what is the role of the Krebs cycle?
To produce ATP from glucose in the presence of oxygen
How is ATP used to power cellular processes?
By phosphorylating molecules to activate them
What are the three major clinical features associated with Alpers’ Syndrome?
Severe epilepsy, loss of developmental skills, and liver failure
Which organelle is responsible for synthesizing lipids, aiding in detoxification of drugs, and metabolizing carbohydrates?
Rough Endoplasmic Reticulum
What is the correct sequence for the process of proteins being secreted from the cell?
Proteins have a secretion signal, mRNA binds ribosome, protein starts to be produced, mRNA export
Which cell organelle is responsible for receiving transport vesicles containing proteins from the Rough Endoplasmic Reticulum and modifying these proteins?
Golgi Apparatus
What is the key enzyme in glycolysis that regulates the speed of the pathway based on the energy needs of the cell?
Phosphofructokinase
Which phase of glycolysis involves the conversion of three-carbon molecules to pyruvate, generating ATP and NADH?
Energy-Releasing Phase
What are the net products generated from one round of glycolysis?
2 ATP, 2 NADH, 2 pyruvate
Which process occurs in the absence of oxygen and is essential for ATP production when oxygen is scarce?
Glycolysis
Which molecule is formed when acetyl-CoA combines with oxaloacetate during the Krebs cycle?
Citrate
What is the primary function of the Krebs cycle in cellular metabolism?
Energy production through oxidation
What is the primary role of protein complexes in the electron transport chain?
Transfer electrons and pump protons
What is the function of Ubiquinone(Q) and Cytochrome c in the electron transport chain?
Shuttle electrons between complexes
What happens when cyanide acts on complex IV in the electron transport chain?
Stoppage of electron transfer to oxygen
How does the electron transport chain utilize the energy from redox reactions?
Drive the synthesis of ATP by pumping protons
What is one of the major effects of poisoning by cyanide or carbon monoxide on cellular metabolism?
Elevated lactate levels in the blood
What is the primary function of ATP in cellular processes?
Transfers a phosphate group to another molecule through phosphorylation
Which statement accurately describes ATP's role as the 'energy currency' of the cell?
ATP is essential for various cell functions and serves as a universal energy carrier
How does ATP contribute to cellular respiration?
ATP causes conformational changes in proteins
In what way does ATP differ from adenosine diphosphate (ADP) in cellular energy processes?
ATP is hydrolyzed to generate ADP and energy
What is the primary function of the central dogma of molecular biology?
Regulation of gene expression
Where does the process of translation occur within a cell?
Cytosol
What is the primary function of the ribosome in a cell?
Protein synthesis
In which cellular organelle does the final stage of gene expression (translation) take place?
Cytosol
Which component carries the growing polypeptide chain during the elongation phase of protein synthesis?
tRNA in P site
What distinguishes free floating ribosomes from membrane-bound ribosomes in a cell?
Synthesis of different types of proteins
What provides stability to the DNA molecule and contributes to its structural integrity?
Phosphodiester bonds
Which groove, formed by the staggered arrangement of nitrogenous bases along the double helix, is wider and deeper?
Major groove
In DNA replication, what enzyme catalyzes the formation of phosphodiester bonds?
DNA polymerase
Which structure is made up of DNA tightly coiled many times around proteins called histones?
Chromosomes
What is the primary role of histones in the process of deacetylation?
Inhibiting transcription
Which type of microtubules is primarily involved in connecting sister chromatids to the spindle apparatus during cell division?
'A' microtubules
'Triplet code' refers to a sequence of how many nucleotides on a DNA or RNA molecule?
Three
'Huntington’s disease' primarily targets which structures in a process called deacetylation?
Histones
'Replication' in cellular division specifically results in the formation of how many double-stranded DNA molecules in the nucleus?
2
'Triplet code' controls the production of which cellular component in the cytoplasm of the cell?
'C' amino acids
What is the information content more accessible in major groove because what is exposed along the double helix?
Nitrogenous bases
What is the primary function of the Krebs cycle in cellular metabolism?
Generation of NADH and FADH2 for ATP production
Which enzyme plays a crucial role in regulating the speed of glycolysis based on the energy needs of the cell?
Phosphofructokinase
In the absence of oxygen, what is the primary pathway for ATP production in cells?
Glycolysis
What happens when cyanide acts on complex IV in the electron transport chain?
It stops all electrons being passed to oxygen
Which phase of glycolysis involves using two ATP molecules to convert one molecule of glucose into two three-carbon molecules of glyceraldehyde-3-phosphate?
Energy-Requiring Phase
How do pathogens manipulate the host cytoskeleton?
By altering actin filament polymerization
What is the purpose of the proton gradient created in the electron transport chain?
To drive ATP synthesis by ATP synthase
What is the net ATP yield per molecule of glucose metabolized through glycolysis?
+2 ATP
What role do Microtubule Organizing Centres (MTOCs) play in cells?
Cytoskeleton structure
What distinguishes intermediate filaments from microtubules and microfilaments?
Their structural stability and diverse protein composition
Why is cellular diversity important in building complex organisms like the human body?
To enable the specialization of cells for different tasks
What are the three major clinical features associated with Alpers’ Syndrome?
Seizures, developmental regression, liver failure
Which organelle aids in the detoxification of drugs and other toxins?
Rough Endoplasmic Reticulum
What is the primary function of the Golgi Apparatus in a cell?
Protein modification and sorting
Which molecule is formed by millions of nucleotides joined together in a long chain?
DNA
What is the role of Pentose Sugar in a nucleotide?
Provides a sugar component to the nucleotide
Which pair always forms bonds in DNA by pairing up?
(Guanine, Thymine)
Which chemical bonds link adjacent nucleotides in a DNA strand?
Phosphodiester bonds
What is the major difference between purines and pyrimidines in nitrogenous bases?
Number of heterocyclic rings they contain
What is the primary role of Ribosomes in protein synthesis?
Synthesize proteins based on mRNA instructions
Which type of cells are unicellular in nature?
Prokaryotic cells
What is a major difference in DNA structure between prokaryotic and eukaryotic cells?
Eukaryotic DNA is circular with proteins
Which organelle is responsible for motility in eukaryotic cells by waving cilia and flagellin?
Centrioles
During which phase of the cell cycle does DNA replication occur?
Interphase
Which type of cell division involves binary fission?
Binary fission exclusively
How does DNA differ in packaging between euchromatin and heterochromatin?
Euchromatin is loosely packed, while heterochromatin is tightly packed
What enzyme catalyzes the formation of phosphodiester bonds during DNA replication?
DNA polymerase
What is the term for the process by which DNA is copied to produce an identical replica?
Replication
Which structure in eukaryotic cells contains the genetic material and directs cellular activities?
Nucleus
What is the primary function of cytoskeletons in eukaryotic cells?
Cellular transport
Which type of ribosomes are present in prokaryotic cells?
70S
In which phase of the cell cycle does DNA condense into tightly packed chromosomes?
Mitosis
Which organelle in plant cells contains DNA in addition to the nucleus?
Chloroplast
What is the primary method of cell motility in prokaryotic cells?
Rigid rotating flagellum
What is the primary function of the centrosome in eukaryotic cells during the late G2 phase?
Serves as the main microtubule organizing center of the cell
What happens to cohesin proteins during anaphase of mitosis?
They lead to the separation of sister chromatids
Which phase of the eukaryotic cell cycle marks the time when the cell has stopped dividing and has left the cycle?
Resting phase (Gap 0)
During which phase of mitosis do chromosomes begin to condense and the nucleolus disappears?
Prophase
During which phase of meiosis do homologous chromosomes line up at the metaphase plate and can undergo crossing over?
Metaphase I
What is the major difference between the process of anaphase in mitosis compared to anaphase I in meiosis?
Sister chromatids separate in mitosis, homologous chromosomes separate in meiosis
What structural feature allows for the formation of chiasmata during meiosis?
Synaptonemal complex
Which process contributes to genetic diversity among gametes during meiosis?
Crossing over
What is the significance of cells resulting from meiosis II being haploid?
It prepares for fertilization to restore diploidy
In which phase of meiosis does the nuclear envelope begin to reform around the separated chromosomes?
Telophase I
Which process is involved in the production of functional gene products like proteins and functional RNAs?
Translation
What is the discipline focused on sequencing, mapping, analyzing, and comparing genomes known as?
Genomics
At the molecular level, which component of a gene encodes and directs the synthesis of proteins, tRNA, rRNA, or other structural RNAs?
DNA
What is the primary function of the Fundamental Dogma in biology?
To link DNA replication and RNA transcription
What is the role of release factors in translation termination?
Assisting in the recognition of stop codons
What occurs in the E site of the ribosome during translation termination?
Drift out of empty tRNA
What defines a polyribosome?
A cluster of ribosomes linked by tRNAs
During which phase of translation does the A site act as the landing site for the next tRNA with an anticodon complementary to the exposed codon on mRNA?
Elongation
What is the primary function of the 5' capping process during RNA processing?
Addition of a methyl-guanosine cap at the 5' end
Which phase of gene expression involves the addition of ~200 adenines to the 3' end of pre-mRNA?
RNA processing
What is the role of promoters in transcription?
Serving as recognition points for RNA polymerase binding
Which phase of translation involves the binding of the 40S ribosomal subunit to mRNA?
Initiation
What is the function of aminoacyl-tRNA synthetases in protein synthesis?
Adding amino acids to tRNA molecules
What is the primary role of splicing in RNA processing?
Removing non-coding introns and joining coding exons
Which structure in tRNA is responsible for carrying a specific amino acid?
'CCA' tail
'Universal Genetic Code' refers to a common language for translating nucleotide sequences into what during protein synthesis?
'Amino acid sequences'
What is the function of ribosomes in protein synthesis?
Making proteins by translating mRNA sequences
What is the primary function of the operator in an operon?
Halts transcription by binding to DNA
In prokaryotic cells, what determines whether an operon is inducible or repressible?
The ability of small molecules to turn it off
Which DNA-binding protein inhibits the expression of genes by binding to the operator?
Repressor
How does the operon differ from a single gene in prokaryotic cells?
An operon operates from a single promoter, while a single gene has multiple promoters
What is the key difference between Rho-dependent and Rho-independent transcription termination strategies?
Formation of a hairpin structure in the RNA transcript
What is the role of the Shine-Dalgarno sequence in protein synthesis?
Complementing the 16S rRNA in the ribosome
How does Rho factor contribute to transcription termination in prokaryotes?
Pulling the RNA transcript and DNA apart
What is the function of the 16S rRNA in prokaryotic ribosomes during translation initiation?
Binds to mRNA Shine-Dalgarno sequence
What happens when C and G rich region on DNA template is approached during transcription?
Hairpin formation in the mRNA
Why does the presence of U nucleotides after the hairpin structure aid in transcription termination?
Weakens mRNA-DNA interaction
What happens when an inducer molecule is present in the trp operon of E.coli?
It binds to the repressor protein, changing its conformation.
What role does the lacY gene play in the lac operon of E.coli?
It is involved in transporting lactose into the cell.
Which statement accurately describes the regulation of the Trp Operon in E.coli?
The repressor proteins are unable to bind to the operator when tryptophan is present.
Which region of DNA is essential for initiating transcription in prokaryotes?
Pribnow box
What is the function of the lacI gene in the lac operon regulation?
Codes for an allosteric repressor protein
What happens in E.coli when lactose is absent in terms of the lac operon?
The repressor protein is inactive allowing transcription.
"What is the primary function of RNA polymerase during transcription initiation?"
"Transcribes mRNA from DNA template."
"What purpose does suspending repressible enzymes serve in cells?"
"Allows energy allocation elsewhere by halting unnecessary processes."
"What differentiates inducible enzymes from repressible enzymes regarding cellular role?"
"Inducible enzymes break down nutrients while repressible enzymes synthesise end products."
What is the primary factor that heavily influences the movement of charged particles in an electric field during gel electrophoresis?
Size of the molecules
In gel electrophoresis, what is the role of the buffer used when loading the gel?
Provide electrolytes to facilitate current movement
What is the purpose of loading DNA ladder (reference of Molecular weight marker) in gel electrophoresis?
To identify the size of DNA bands
At which end of the gel is the Cathode (-) placed during electrophoresis?
Top loading end
What is the purpose of using 70% ethanol in the biological safety cabinet?
To disinfect items inside the cabinet
Why is it important to warm cell culture media and additives to 37°C?
To maintain the viability of cells
What is the expected outcome of using trypan blue in viability staining?
Viable cells will have intact membranes and not be colorized
Why should movements within and outside the biological safety cabinet not be rapid?
To maintain the sterile airflow inside the cabinet
What is the significance of labeling materials used for cell culture with initials, date, and additives?
To track and ensure proper identification of materials
How does ethanol (EtOH) contribute to viability staining using trypan blue?
It kills bacteria by rupturing their cell membranes
What is the primary function of sphingomyelin in the cell membrane?
Participates in signaling pathways
Which characteristic best describes integral membrane proteins in the cell membrane?
Permanently embedded within the membrane
What is the main role of carbohydrates in the cell membrane?
Assist in cell recognition
Which adhesion molecule is involved in cell-cell adhesion?
Cadherin
What is the primary function of CAMs (Cell Adhesion Molecules) in cellular communication?
Maintain physical contact between cells
How do phospholipids contribute to the selective permeability of the cell membrane?
By allowing certain molecules to diffuse across the membrane
What factor heavily influences the movement of charged particles in an electric field in gel electrophoresis?
New charge of molecules
In gel electrophoresis, what is the primary function of the gel matrix made out of agarose?
Retard the movement of molecules based on density
What is the buffer's role in gel electrophoresis?
Provide electrolytes to facilitate current movement
When loading the gel in gel electrophoresis, what is the purpose of mixing the DNA sample with loading buffer/dye containing a high-density molecule like sucrose?
Help DNA sink to the bottom of the well
What is the purpose of warming cell culture media and additives to 37˚C in a water bath when preparing fresh media?
To promote cell growth
Why is it essential to label all materials used for cell culture with initials, date, and additives?
For proper identification and tracking
In viability staining using trypan blue, why are live cells with intact membranes not colorized?
The dye does not penetrate live cells
What is the function of ethanol in treating cells by rupturing the cell membrane?
To sterilize by disrupting bacterial membranes
Why is it important to avoid rapid movements within and outside the biological safety cabinet?
To maintain sterile airflow
What is the reason behind seeding low cell count/density leading to cell death?
Inadequate nutrient availability
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